Mr. Bautista, a Toronto Blue Jays outfielder, isn't just leading the majors in home runs this year. He's dominating the American League race by near-Ruthian proportions, in percentage terms. Through Sunday's games, Mr. Bautista had 52 home runs, nearly 37% more than the AL's next-best homer-hitters, Miguel Cabrera and Paul Konerko (38).

When assessing the race this way—which takes into account how difficult it was to hit a homer in a given season—this gap between first place and second is the largest in the AL since 1956, and the second-largest since Ruth retired in 1935. (Major-league-wide, Mr. Bautista has 24% more homers than Albert Pujols, the 10th-biggest margin since Ruth's retirement.)

The Babe, of course, was on a different level. In four different seasons, Ruth's homer total more than doubled the next-best slugger in either league. In 1920, Ruth's 54 homers nearly tripled that of runner-up George Sisler (19).

In more recent times, the dominance of Mr. Bautista (who had 59 career homers before this year) is reminiscent of Cecil Fielder's 1990 season. Mr. Fielder entered that year with 31 career homers, then hit 51—while no one else in the AL reached 40.